Vogel, D., Balakrishnan, R., “Interactive public ambient displays: transitioning from implicit to explicit, public to personal, interaction with multiple users”, Proc. 17th annual ACM symposium on user interface software and technology, 2004, pp. 137-146, discloses an interaction framework for sharable, interactive public ambient displays that support the transition from implicit to explicit interaction with both public and personal information. The display and interaction techniques exploit implicit contextual cues such as body orientation and user proximity to the display, and explicit actions such as hand gestures and touch screen input. When the user approaches the display and provides an implicit cue such as pausing for a moment, the system should enter the subtle interaction phase. More detailed descriptions of the notifications and/or the current state of the available public information are displayed.
A problem of the known method is that the controls provided to the user are relatively unresponsive, in that they are provided in a binary manner, depending essentially on the distance. The detection of cues serves merely to cause transitions between states providing different functionalities, which are selected in dependence on the distance of the user to the display.